JPH11236157A - Reversing device, and image forming apparatus provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversing device capable of avoiding defective carriage of a transfer material, and an image forming apparatus provided with the reversing device. SOLUTION: A reversing device is provided with a reversing drive roller 69 to reverse and discharge a paper P, the reversing drive roller 69 holds the paper sheet P between a reverse roller 67 which is a carrying roller and an oscillating reverse branching claw 84 to be energized toward the reverse roller 67, and carries the paper P to the prescribed position by applying the carrying force in the forward direction to the paper P by the reverse roller 67. and carries the paper P in the reverse direction by the reversing drive roller 69 arranged on the downstream side of the reverse branching claw 84 after the carriage in the forward direction. A jump base 89 to separate at least the of the paper P during the carriage in the forward direction of the paper P from the reversing drive roller 69 is provided in the vicinity of the reversing drive roller 69. At least the tip of the paper P can be separated from the reversing drive roller 69 during the carriage in the forward direction. At least tip of the paper P can avoid defective carriage of the paper P.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversing device for reversing a transfer material such as plain paper and an image forming apparatus provided with the reversing device.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus having a reversing device for carrying by a branching claw, Japanese Utility Model Application Laid-Open No. 3-107454.
No. is known.

In this conventional sheet reversing device, as shown in FIG. 4, a sheet conveyed from a carry-in path 101 with an image surface facing upward has a sheet leading edge added to a reversing roller 102 and a curved surface of a branch claw 103. Turn path 1 along section 104
Enter 06. Here, the shape of the curved surface portion 104 of the branch claw 103 is formed so as to bite into the inner peripheral surface of the roller as it proceeds in the rotation direction of the roller constituting the reversing roller 102.

When the trailing edge of the sheet passes through the opposite portion between the curved surface portion 104 of the branch claw 103 and the reversing roller 102, the solenoid 107 is turned on, and the hit roller 108 is applied to the rotating return roller 109. Pressing through the paper. Then, the paper is sent out along the return path 106 according to the rotation of the return roller 109, and
The sheet is passed through the sheet ejection roller 111 of the sheet ejection path 110 through the sheet ejection path 05. By this process, the sheet is sent out with its back and front reversed.

[0005]

However, in such a conventional image forming apparatus having a reversing device which carries out conveyance by a branching claw, a pressure is applied to the branching claw 103 so that the leading end of the transfer material in the conveying direction is in the reverse direction during the conveyance. There is a possibility that the interference with the return roller 109, which is a transporting means for transporting the paper, may occur and a problem such as a transport failure may occur.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a reversing device and an image forming apparatus having the reversing device capable of avoiding transfer material conveyance failure.

[0007]

In order to achieve the above object, a reversing device according to a first aspect of the present invention has a reversing and discharging means for reversing and discharging a transfer material, wherein the reversing and discharging means comprises a conveying roller and a conveying roller. The transfer material is sandwiched between the inversion branch claw pressed against the transfer material, and the transfer roller applies a transfer force in the forward direction to the transfer material to transfer the transfer material to a predetermined position. In a reversing device that conveys the transfer material in a reverse direction by a reverse conveyance means disposed on the downstream side of the claw, in the vicinity of the reverse conveyance means, at least the front end of the transfer material is transferred during the forward conveyance of the transfer material. It is characterized in that an isolating means for isolating from the reverse conveying means is provided. In this configuration, since at least the leading end of the transfer material can be separated from the reverse conveying means by the separating means during the forward conveying of the transfer material, the reversing device can prevent at least the leading end of the transfer material from interfering with the reverse conveying means. Can be obtained.

According to a second aspect of the present invention, in the reversing device according to the first aspect, the isolating means is provided on a side of the transfer material introduction portion of the reverse direction conveying means, and is configured to transfer the transfer material in the normal direction. And a guide member that is separated from the reverse conveying means. In this configuration, at least the front end of the transfer material can be separated from the reverse conveyance means by the guide member during the forward conveyance of the transfer material. It is possible to obtain a reversing device that can prevent interference.

An image forming apparatus provided with a reversing device according to a third aspect of the present invention has a reversing / discharging means for reversing and discharging the transfer material, and the reversing / discharging means is pressed against the transport rollers. The transfer material is sandwiched between the reversing branch claws, and the transfer roller applies a conveying force in the forward direction to the transfer material to convey the transfer material to a predetermined position. In an image forming apparatus including a reversing device that conveys a transfer material in a reverse direction by a disposed reverse conveyance device,
An isolation means is provided near the reverse transport means for isolating at least the leading end of the transfer material from the reverse transport means during the forward transport of the transfer material. In this configuration, since at least the leading end of the transfer material can be separated from the reverse conveying means by the separating means during the forward conveying of the transfer material, the reversing device can prevent at least the leading end of the transfer material from interfering with the reverse conveying means. An image forming apparatus provided with:

According to a fourth aspect of the present invention, there is provided an image forming apparatus having the reversing device according to the third aspect, wherein the separating means is provided on the side of the transfer material introduction portion of the reverse conveying means. And a guide member that separates the transfer material from the reverse transport means during the forward transport. In this configuration, at least the front end of the transfer material can be separated from the reverse conveyance means by the guide member during the forward conveyance of the transfer material. An image forming apparatus provided with a reversing device capable of preventing interference can be obtained.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a main part of a reversing device according to the present invention, FIG. 2 is a diagram showing a reversing discharge / double-side system including a reversing device of an image forming apparatus according to the present invention, and FIG. 1 is a schematic configuration diagram of an image forming apparatus provided.

As shown in FIG. 3, an image forming apparatus provided with a reversing device includes a reading system 1, a writing system 2, a paper feeding system 3, an image forming system 4, a fixing system 5, and a reversing discharge system. -It has a double-sided system 6.

The reading system 1 irradiates a document with a light source such as a fluorescent lamp and reads the reflected light using an optical system including a mirror and a lens system. The writing system 2 includes a reading system 1
The writing system 2 performs exposure 2a based on the image read by
To form a latent image on the photoreceptor 4a. The paper feed system 3 supplies paper P as a transfer material.

The image forming system 4 includes a photosensitive member 4a and a photosensitive member 4a.
A charger 4b for uniformly charging the surface; a developing device 4 for attaching a toner charged to a polarity opposite to that of the latent image to the latent image to form a visible image
c, a transfer unit 4d for transferring a toner image to the sheet P by applying a charge having a polarity opposite to the charging polarity of the toner to the sheet P from the back side of the sheet P, and removing the latent image charge on the photoconductor 4a after the transfer. An electric device 4e and the like are provided, and a visible image of the toner is formed on the photoconductor 4a and transferred to the paper P.

The fixing system 5 fixes the toner on the paper P. The reverse discharge / double-sided system 6 includes a straight (normal) discharge for feeding the sheet P to a first path A which is a discharge path without reversing the sheet P, and a second path B for feeding a sheet conveyed face up. And the paper P, which has been copied on one side, is reversed via the second path B for copying on both sides.
The sheet is conveyed to a third path C between the transfer path 5 and the lower conveyance guide plate 76 and both-sided copying is performed, and the sheet is discharged to the first path A for both-side discharge.

In this image forming apparatus, as shown in FIG. 3, a writing system 2 forms a latent image on a photoconductor 4a based on an image read by a reading system 1, and a photoconductor 4 is formed by an image forming system 4. A visible image of the toner is created on 4a.

On the other hand, the paper P supplied from the paper feed system 3 is transported to the image forming system 4. In the image forming system 4, the toner is transferred to the sheet P, and the sheet P on which the fixing is completed is inverted and discharged.
The sheet is conveyed to the duplex system 6.

As shown in FIG. 2, the reversal discharge / double-sided system 6 includes a first path A for straight (normal) discharge of the sheet P to the outside of the image forming apparatus and a sheet P in the reversal discharge / double-sided system 6. A second path B for inverting and ejecting P, and a sheet P is inverted in the inverting ejection / double-sided system 6 and conveyed to the two-sided system, re-supplied to the image forming system 4, and formed through the above process. And a third path C for discharging the image to the outside of the image forming apparatus through the first path A.

As shown in FIGS. 1 and 2, in the reverse discharge / double-sided system 6, in the first path A composed of the lower surface of the upper discharge paper guide plate 61 and the upper surface of the intermediate discharge paper guide plate 64, an image forming apparatus is used. The paper P is discharged straight (normal) to the outside.
In the second path B, the sheet P is reversed in the reverse discharge / double-sided system 6 and discharged. In the third path C, the sheet P is reversed in the reverse discharge / double-side system 6, conveyed to the reverse discharge / double-side system 6, re-supplied, and imaged through the above-described process.
The paper is discharged to the outside of the image forming apparatus through the path.

The reverse discharge / double-sided system 6 includes a paper discharge branching claw 63 for switching the paper P passing through the fixing system 5 to a first path A and second and third paths B and C, and a lower paper discharge guide plate. At the end of the second and third paths B and C between the sheet-return intermediate guide plate 62 and the sheet discharge intermediate guide plate 64, a reversal entrance path composed of a reversal entrance upper guide plate 65 and a reversal entrance lower guide plate 71, A detection sensor 66 provided on the guide plate 65 for detecting the rear end of the sheet P in the traveling direction, a reversing roller 67 provided on the downstream side of the detection sensor 66, and a leading end alternately disposed between the reversing rollers 67 in the axial direction. Are nested with each other, are urged upward toward the reversing roller 67, and are swingable reversible branch claws 84 which are pressed against the reversing roller 67.
And a reverse drive roller 69 that reverses the transport direction of the sheet P across the sheet P by the downward movement of the reverse rotation driven roller 68, and a position regulating side fence 88 that regulates the side position of the sheet.
A double-side driven roller 72 and a double-sided driving roller 73 for transporting the paper P whose transport direction is reversed, and a double-sided branching claw 74 for switching the paper whose transport direction is reversed toward the second path B or the third path C; The transport left driving roller 77 and the transport left driven roller 78 for transporting the paper P in the third path C;
Transport right drive roller 7 for further transporting paper P in path C
9, a conveyance right driven roller 80, a paper re-feeding guide plate 81 for guiding the paper P in the paper re-feeding direction, a paper feeding grip roller 82 for re-feeding the paper P toward the image forming system 4, and a paper feeding grip roller 82. The paper grip roller driven roller 83 and the discharge intermediate guide plate 6
4 together with the re-discharge guide plate 85 constituting the second path B
And a discharge driven roller 87 and a discharge drive roller 86 for discharging the paper P, and a jump table 89 as isolation means provided on the reverse conveyance guide plate 70 near the reverse rotation drive roller 69. .

Next, referring to FIG. 2, the operation of the reversing discharge system including the reversing device of the present invention will be described. The sheet P that has passed through the fixing system 5 is divided into a first path A and second and third paths B and C by switching the sheet discharge branch claws 63. That is, the sheet is transported to the reverse discharge / double-sided system 6 by switching the discharge branch claw 63 in the solid line direction, and straight discharge is performed by switching in the broken line direction.

When the discharge branching claws 63 are switched in the direction of the solid line, the lower discharge guide plate 62 and the intermediate discharge guide plate 64 are provided.
Through the second and third paths B and C between the reverse entrance guide plate 65 and the reverse entrance lower guide plate 71. The reverse entrance guide plate 65 is provided with a detection sensor 66 for detecting the rear end of the sheet P in the traveling direction. The tip of the reversing branch claw 84 is pressed upward. Further, the tip of the reversing branch claw 84 is alternately nested between the reversing rollers 67 in the depth direction (roller axis direction), and the paper P enters between the reversing branch claw 84 and the reversing roller 67. The paper P is pressed against the reversing roller 67 by the pressure of the reversing and branching claw 84 to generate a conveying force,
Conveyed.

Here, as shown in FIG. 1, when the sheet P is pressed against the reversing roller 67 by the pressure of the reversing branch claw 84, the sheet P is conveyed with a conveying force, and enters the reversing driving roller 69, a reversing conveyance guide is provided. Since the jump table 89 is provided on the plate 70, the leading end of the sheet P in the transport direction can jump over the reverse drive roller 69 by using the jump table 89. That is, the jump table 89 guides the leading edge of the sheet P in the transport direction so as not to interfere with the reverse rotation drive roller 69. For this reason, the paper P can be transported without the leading edge of the paper P in the transport direction being caught on the reverse rotation driving roller 69 which is always rotating in the reverse direction to the transport direction. Further, a reverse rotation driving roller 69 is provided as a separating means so as to be able to protrude and retract on the reverse conveyance guide plate 70 so as to be in a submerged state when the paper P is conveyed in the forward direction and to protrude when conveyed in the reverse direction. However, in this case, the configuration is more complicated than providing a jump stand.

When the rear end of the sheet P passes through the reversing branch claw 84, the position regulating side fence 88 sandwiches the sheet P,
Regulate the position of the side. While the position is regulated, the reverse follower roller 6 is
8, the sheet P is pinched together with the reverse rotation drive roller 69, and the conveying direction of the sheet P is reversed. When the sheet P is conveyed and sandwiched between the two-side driven roller 72 and the two-sided driving roller 73, the reverse rotation driven roller 68 returns to the original position indicated by the solid line, the position regulating side fence 88 also spreads, and returns to the original standby position. Return.

The paper P is conveyed toward the double-sided branch pawl 74 by the double-sided driven roller 72 and the double-sided driving roller 73, and by switching the double-sided branch pawl 74, the second path B is set at the solid line position.
At the broken line position, is conveyed in the double-side re-feeding direction of the third path C, and is returned to the image forming system 4 via the roller pair including the paper feeding grip roller 82 and the paper feeding grip roller driven roller 83. Paper is fed, and double-sided image formation is performed.

According to the above embodiment, there is provided a reverse drive roller 69 for inverting and discharging the sheet P, and the reverse drive roller 69 is urged toward the reverse roller 67 and the reverse roller 67, which are conveying rollers. Swingable reversing branch claw 8
4, the sheet P is conveyed to a predetermined position by applying a forward conveying force to the sheet P by the reversing roller 67, and after the sheet P is conveyed in the forward direction, the sheet P is located downstream of the reversing branch claw 84. In the reversing device for transporting the sheet P in the reverse direction by the disposed reverse drive roller 69, a jump is provided near the reverse drive roller 69 to isolate at least the leading end of the sheet P from the reverse drive roller 69 during the forward transport of the sheet P. Since the table 89 is provided, at least the leading end of the paper P can be isolated from the reverse rotation drive roller 69 during the forward transport, and the transport failure of the paper P at least at the leading end can be avoided. Further, immediately after the rear end of the sheet P has separated between the reversing branch claw 84 and the reversing roller 67, that is, before reaching the jump table 89, the reverse conveyance of the sheet P is started. No interference with 89.

In the above embodiment, the case where paper such as plain paper is used as the transfer material has been described. However, in addition to the paper such as plain paper, other paper can be used as long as the original image can be transferred by electrophotography. Can also be applied.

The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention.

[0029]

As described above, according to the reversing device of the first aspect, there is provided a reversing / discharging means for reversing and discharging the transfer material, and the reversing / discharging means is pressed against the conveying roller and the conveying roller. The transfer material is sandwiched between the reversing branch claw and the transfer roller, and the transfer material is applied to the transfer material in a forward direction to convey the transfer material to a predetermined position. In a reversing device that conveys a transfer material in a reverse direction by a reverse conveyance device disposed on a downstream side, in the vicinity of the reverse conveyance device, at least the front end of the transfer material is moved in the reverse direction during the normal conveyance of the transfer material. Since the separation means for separating the transfer material from the transfer means is provided, at least the front end of the transfer material can be separated from the reverse transfer means by the separation means during the forward transfer of the transfer material,
Therefore, it is possible to prevent the at least the leading end of the transfer material from interfering with the reverse conveying means, and to obtain a reversing device capable of avoiding poor conveyance.

According to a second aspect of the present invention, in the reversing device according to the first aspect, the isolation means is provided on a side of the transfer material introduction portion of the reverse conveyance means, and the transfer material is moved in the forward direction. Since the guide member is separated from the reverse conveyance means during conveyance, at least the leading end of the transfer material can be separated from the reverse conveyance means by the guide member during the forward conveyance of the transfer material. It is possible to obtain a reversing device capable of preventing at least the front end of the material from interfering with the reverse conveying means.

According to a third aspect of the present invention, there is provided an image forming apparatus provided with a reversing device, wherein the reversing and discharging unit reverses and discharges the transfer material. The transfer material is sandwiched between the reversing branch claw and the transfer roller, and the transfer roller applies a transfer force in the forward direction to the transfer material to transfer the transfer material to a predetermined position. An image forming apparatus provided with a reversing device that conveys the transfer material in a reverse direction by a reverse conveyance device disposed on a side of the image forming apparatus; Since the separating means for separating the leading end from the backward conveying means is provided, at least the leading end of the transferring material can be separated from the backward transferring means by the separating means during the forward transferring of the transferring material, and therefore, at least the leading end of the transferring material is separated from the backward transferring means. Reverse direction hand Bets can be prevented from interfering, it is possible to obtain an image forming apparatus provided with an avoidance Dekiruru reversing device transportation failure.

According to a fourth aspect of the present invention, there is provided the image forming apparatus having the reversing device according to the third aspect, wherein the separating means is provided on the side of the transfer material introduction section of the reverse conveying means. The guide member is provided on the transfer member so as to separate the transfer material from the reverse conveyance unit during the forward transfer, so that at least the leading end of the transfer material can be separated from the reverse transfer unit by the guide member during the forward transfer of the transfer material. In spite of the simple configuration, it is possible to obtain an image forming apparatus provided with a reversing device capable of preventing at least the leading end of the transfer material from interfering with the reverse conveying means.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a reversing device according to the present invention.

FIG. 2 is a diagram illustrating a reversal discharge / double-side system including a reversing device of the image forming apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram of an image forming apparatus provided with a reversing device according to the present invention.

FIG. 4 is a diagram showing a conventional reversing device.

[Explanation of symbols]

 P paper (transfer material) 67 reversing roller (conveying roller) 69 reverse rotation driving roller 84 reversing branch claw 89 jump table (isolation means)

Claims (4)

[Claims] 1. A reversing / discharging unit for reversing and discharging a transfer material, wherein the reversal / discharge unit sandwiches the transfer material between a transport roller and a reversing branch claw pressed against the transport roller to transport the transport material. The transfer material is conveyed to a predetermined position by applying a forward conveyance force to the transfer material by the roller, and after the conveyance in the forward direction, the transfer material is moved in the reverse direction by the reverse conveyance means disposed downstream of the reversing branch claw. A reversing device, provided near the reverse transporting means, for isolating at least a leading end of the transfer material from the reverse transporting means during forward transporting of the transfer material. . 2. The image forming apparatus according to claim 1, wherein the separating unit is a guide member provided on a side of the transfer material introducing unit of the reverse conveying unit, and separating the transfer material from the reverse conveying unit during the forward conveying. Item 7. The reversing device according to Item 1. 3. A reversing / discharging means for reversing and discharging the transfer material, wherein the reversing / discharging means interposes the transfer material between a transport roller and a reversing branch claw pressed against the transport roller to transport the transport material. The transfer material is conveyed to a predetermined position by applying a forward conveyance force to the transfer material by the roller, and after the conveyance in the forward direction, the transfer material is moved in the reverse direction by the reverse conveyance means disposed downstream of the reversing branch claw. An image forming apparatus provided with a reversing device for transporting the transfer material in the vicinity of the reverse transport device, wherein an isolating device is provided near the reverse transport device to isolate at least a leading end of the transfer material from the reverse transport device during the forward transport of the transfer material. An image forming apparatus comprising a reversing device characterized by the above-mentioned. 4. The image forming apparatus according to claim 1, wherein the separating unit is a guide member provided on a side of the transfer material introducing unit of the reverse direction conveying unit, and separating the transfer material from the reverse direction conveying unit during the forward direction conveying. Item 4. An image forming apparatus comprising the reversing device according to Item 3.